1. Field of the Invention
The present invention relates generally to containers for delivery of prepared food and particularly of foods which are desirably maintained at an adequate temperature during delivery.
2. Description of the Prior Art
Fast food restaurants have proliferated to such an extent that the percentage of people who frequent these establishments on a regular basis has increased greatly. Among the reasons for this increase is the availability of quickly prepared foods which may be consumed at the restaurant or may be carried out and consumed at a later time. Many such restaurants are equipped with drive though windows to facilitate such take-out service.
Typically, take-out food is placed within a disposable container which, even if equipped with thermal insulated material, does not retain heat for an appreciable amount of time thereby allowing the food contained therein to cool relatively rapidly. Much time and effort has been devoted to make possible the economical delivery of fast food in a satisfactorily hot condition in a disposable heat-retaining food container. For example, U.S. Pat. No. 5,445,286 to Guimarin discloses a heat retentive pizza box having a heating element comprised of water filled pockets which may be preheated in a microwave oven. The microwaved heating element serves to maintain the temperature of the pizza during delivery. Similarly, U.S. Pat. No. 4,567,877 to Sepahpur discloses a heat storage food container including a compartment for holding a microwavable thermal storage medium, such as wet sand. When preheated in a microwave oven, the wet sand retains the heat of the food placed in the container. U.S. Pat. No. 4,777,930 to Hartz and U.S. Pat. No. 5,880,435 to Bostic both disclose food delivery containers having a heat conductive pouch containing a quantity of a latent heat retaining substance which may be preheated to an initial temperature.
A major drawback of each of the above devices is the time required to preheat the heating element. This is particularly disadvantageous with drive-through take-out food service where food orders are delivered rapidly and continuously during the restaurant's peak operating hours. Accordingly, it would be desirable to provide an economical disposable heat maintaining food container which is quickly preheated to a desired temperature.